scope:

This standard describes the adaptation of the narrowband ISDN User Part (ISUP) for the support of narrowband ISDN services independent of the bearer technology and signalling message transport technology used.

This standard is written as a set of exceptions to T1.113-2000. In some cases these exceptions are displayed by quoting the original text of T1.113-2000 with revision marks. (Deleted text is shown using strikeouts, and added text is shown underlined.)

The protocol defined by this standard is the call control protocol to be used between "Serving Nodes". This protocol is called the "Bearer Independent Call Control" (BICC) protocol. Between Serving Nodes the control of bearers is provided by other protocols not specified by this standard.

Three types of Serving Node (SN) are defined:

• Interface Serving Node (ISN) -Provides an interface to circuit switched networks.

• Transit Serving Node (TSN) -Provides transit functionality, for call and bearer, within one network using the BICC protocol.

• Gateway Serving Node (GSN) -Provides inter-network gateway functionality, for call and bearer, using the BICC protocol.

The main body of this document defines the protocol at Transit Serving Nodes and Gateway Serving Nodes. The scope is thus as shown in Figure 1/T1.672.1.

In defining the procedures for BICC at an Interface Serving Node, this standard also defines how BICC interworks with other protocols. These descriptions are contained in Annex E/T1.672.4 to this standard.

This standard also contains Annex H/T1.672.4, of relevance to a Call Mediation Node, where call control functions may reside without any bearer control capability.